Kate gathered three boxes of the same size made of different materials: glass, clear plastic, and aluminum painted black. she placed them on a window sill in the sun for an hour and then measured the warmth of the air in each box. in this experiment, the time of an hour is a(n)
dependent variable
constant
control
independent variable

Constant Variable

In an experiment, the measurable quantities which are kept same and do not change throughout the experiment are known as constant variables.

In the given experiment, Kate keeps the three boxes in the sun for the same amount of time i.e one hour each. The time-variable does not change and remains constant throughout the experiment. Therefore, time of an hour is a constant hour.

increases it

the chart show the masses and velocities of two colliding objects that stick together after a collision.

according to the law of conservation of momentum, the momentum of the object after the collision is  

answer

1,500

kg • m/s.